Eide-san may have encountered the culprit at the shooting range. Instead of she being there, the culprit was the one shooting, which may explain why she wouldn't have with her the crossbow she worked so hard to customize with runes.

Afterwards, together they went together to the bar, and Eide-san was killed. What I'm not entirely sure yet is if Eide-san knew something about what was going on, because...something about her expression continues to bother me. It didn't look like someone who was betrayed, it was too peaceful.

Of course, we'd need to account for when the culprit would have time to collect the pills from the infirmary. If this was a casual encounter at the shooting range, it's unlikely they already had them.

[She's just theorizing, of course she may be wrong]